Erreur: Le serveur distant a retourné une erreur: (401 non autorisé

Je reçois ce message d'erreur lorsque j'essaie d'accéder à des formes qui appelle WCF fonctions.
Effectivement, il fonctionne sur ma machine locale mais quand il est dans le serveur, ce genre de choses se produit 🙁

Source De L'Erreur:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  

Trace De La Pile:

[WebException: The remote server returned an error: (401) Unauthorized.]
System.Net.HttpWebRequest.GetResponse() +6115603
System.ServiceModel.Channels.HttpChannelRequest.WaitForReply(TimeSpan timeout) +48
[MessageSecurityException: The HTTP request is unauthorized with client authentication scheme 'Anonymous'. The authentication header received from the server was 'Negotiate,NTLM'.]
System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) +9439503
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) +345
Project.WCFUser.Users.HaveAccess(String userid, String filename) +0
Project.WCFUser.Users.HaveAccess(String userid, String filename) in C:\Documents and Settings\MyPC\My Documents\Visual Studio 2010\Project\Project\Project\Service References\Users\Reference.cs:71
Project.View.User.Details.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\MyPC\My Documents\Visual Studio 2010\Project\Project\Project\View\User\Details.aspx.cs:50
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
System.Web.UI.Control.OnLoad(EventArgs e) +91
System.Web.UI.Control.LoadRecursive() +74
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2207